分子生物学第五章.pptx

第五章 蛋 白 质 翻 译来源：不详

5.1.根本元件5.2.GeneticCode5.3.peptidesynthesize5.4.保证peptide准确翻译的机制5.5.CentralDogma的开展

5.1.基本概念

●thesecondstepofgeneexpression●Multiplecomplexassessment●tRNAasaadapterforcodonaminoacid●tRNAloadingaabyaa-tRNAaasynthetase(AARS)paracodon●tRNArecognitioncodonbyanti-codon

●codon;universaltriplexcodon twoofthreereadingcodon paracodon codonincodon●codondegeneracy;wobblehypothesis isoacceptor●codonusage(codonbias)●mechanismofaccuratetranslation initiation,loading,elongation,proofreading

5.2.基本元件(Source:IrvingGeis/PeterArnold,Inc.)

5.1.1.tRNA●miniRNA,4s,(70-80Nt)●tRNAphe,77Ntcloverleafform(1964HollyR.)●5arms4loops●Ntmoremodifiedbymethylation

DHUloop;contactwithAARSanti-codonloop;34thiswobblebaseaaacceptarm;loadingaaat3?end TΨCloop; contactwith5srRNAextraloop;classificationmarker?34 Itype;3-5Nt3/4tRNAIItype;13-21Nt(来源：分子生物学〔2007〕，郑用琏，第179页)

??Capping ?Cap0:m7GpppXpYp ?Cap1:m7GpppXmpYp ?Cap2:m7GpppXmpYmp ?HelpthesplicingofthefirstintronPre-RNAtailing ?Apoly(A)tail(50-200±)beaddedat-20Nt± tailingsignal(AAUAAA)from3’-endofPre-RNA ?SpecificendonulceaserecognizesAAUAAAand thefollowingGUGUGUG,cutswithinthe sequence,addingpoly(A)sat3’-end

??RNAinternalmethylation –m5C –m6A –ModificationsoftRNAsPre-RNAsplicing ?IntronsbeclassifiedintoI,II,IIIbyjunctionsequence ?GroupIsplicingmodel:5’exonUintronGexon3’????CCS(centralcoresequence)Internalguidesequence(IGS):withintheintroncloseto5’junctionseq3timesoftrans-esterificationbetweenGURNAauto-splicingasRibizyme?GroupIIsplicingmodel:5’exonGUGCGB.SPyAU -exon3’?GroupIIIsplicingmodel:5’exonGUintronAG exon3’,SnRNAs

5-1?tRNA ?miniRNA,4s,(70-80Nt) ?Ntmoremodifiedbymethylation ?tRNAphe,77Ntcloverleafform ?Aaacceptarm,DHUloop(contactwithAARS),anti- codonloop,T